I need to calculate the flow rate of air through a 3/4" orifice from the pressurized side of a 1000 PSI (~250 cu ft at pressure) tank to the open atmosphere and know the time it will take to release 20% - 35% - 50% of the volume of the pressure tank.

Please note that q1 is on p1 and T1. To have it on standard conditions that flow should be converted: q=13947 m3/h; p=101325; T=288K

Mass of air in the tank will change over time as air flows out of the reservoir and on 50% of pressure 50% of mass will be in it (volume is the same).For 1" pipe 3/4" diameter I get 202 m3/h which is almost the same as without it (q1=205 m3/h).

HiMy problem is very similar to the previous one. I need to know how internal pressure i need to have in a reservoir of 8 m3, to achieve a discharge mass flow of 45 kg / min instantaneously via an outlet 2.5".